What forces drive D&D history?

[Shroomy]

What forces drive the history of a D&D world?

The need for ruins or tombs full of treasure in the present day.

 

[Ry]

The need for ruins or tombs full of treasure in the present day.

I know it was intended as flippant, but this is absolutely the best answer I've seen from a design point of view (including my initial guess).

 

[Weregrognard]

Real history is the rise and fall of cultures - Sumeria, the Hittites, the Greeks, the Romans, the British Empire, Nazi Germany - so I wouldn't expect fantasy history to be very different. The story of the Roman Empire in particular has a powerful grip on the Western mind. Fantasy civilisations tend to end in more dramatic, cataclysmic fashion than those in the real world. Always with a bang, never a whimper.

The manner of their passing reflects present day concerns. For example the Suel Empire in Gygax's Greyhawk ended by the Invoked Devastation and Rain of Colorless Fire seems to be a metaphor for nuclear war, written as it was during the Cold War. These days you'd expect to see empires destroyed by climate change or hubris.

CATACLYSMS! Blackmoor (in Mystara) blew themselves up, The Anauroch desert (Forgotten Realms) was once green, THE Cataclysm (Dragonlance), the Mournland (Eberron), the ENTIRE Dark Sun world. These are some examples that come to mind. Cataclysms seem to shape D&D history too.

 

[Thornir Alekeg]

History is driven by change. Change of cultures, climate, power, etc.

D&D world histories are also driven by the change of editions (the wasting of Greyhawk, the rise of Eberron, the disappearance of so many 2e worlds).